Cameraman John Chater sharpens his lens over the earth of the Land Institute in Salina, Kan. "Nothing's happening," he replies.

"There is, there is! There's so much happening." Koons Garcia, 63, is enthusiastically recounting the exchange at a screening of her film "Symphony of the Soil."

While she admits few filmmakers would be foolhardy enough to make a movie about dirt, Koons Garcia's zeal for earth and organics makes her a fitting maestro for her latest project.

Known as the widow of Grateful Dead frontman Jerry Garcia and for her 2004 documentary opposing genetically modified organisms, "The Future of Food," Koons Garcia has evolved from passionate filmmaker to steadfast environmentalist.

The 103-minute documentary marks the next chapter of her career: re-envisioning soil as an essential yet underappreciated resource that sustains many forms of life, including the crops that feed us. Although few think of dirt as scarce, in the United States, topsoil - the uppermost 6 to 8 inches of earth rich in minerals and alive with microbes - is degrading in quality and quantity.

According to the National Academy of Sciences, cropland is eroding at least 10 times faster than the time it takes to replace lost soil. Parts of the Midwest are nearly stripped of topsoil. Koons Garcia fears it will be gone within 30 years if industrial agriculture practices relying on chemicals and over-farming continue.

"We feel that we can waste (soil), because we have so much; but we can't really do that anymore. There's not enough left to waste," she says. "We waste something, plow it up and (the topsoil) blows away and we say, 'Oh, we'll go west.' We are west - this is it."

Vanishing resource

In the film, which is being screened around the country and is set for wide release in spring, Koons Garcia casts soil as the protagonist, highlighting its value with scientific backing. She makes a case for using regenerative methods such as compost application and cover cropping, and re-evaluating the consequences of growing certain crops, such as corn, for biofuel.

"The way that we farm soil in most situations is not with an eye on the future - it's pretty exploitive," says Kate Scow, a chief adviser on the film and professor of soil science and microbial ecology at UC Davis. "That has led to a lot of degradation of soil."

Koons Garcia and the Lily Films team traveled to India, Africa, Europe and North America, filming dirt, compost piles and those who prosper from giving back to their land.

Along the way she met farmers who transitioned from chemical to organic farming. In Punjab, India, Jaspal Singh Chattha, a biodynamic, post-Green Revolution farmer, fascinated Koons Garcia with his improvised, soil-regenerating methods.

Patrick Holden, farmer and head of Britain's Soil Association, inspired her with his deep connection to the earth captured in a unique phrase, describing fertile, functioning soil as "in good heart," a visible theme throughout the film.

Koons Garcia was touched by the connections between people and their land. Countries such as India, which have farmed land for thousands of years, husbanded resources with a less predatory relationship than Americans, she notes. The United States "started out with so much natural wealth that we don't deal well with limits. ... But soil is finite."

Experiments as teen

Inside the '50s-era redwood guest house behind her Mill Valley home, Koons Garcia's animated energy is joined by the rambunctious play of her Dalmatians Nico and Honeybee. Her poetic metaphors about soil and society are interrupted by Nico's intermittent springs across a sectional.

Nestled in the shoulder of Mount Tamalpais, her backyard hosts a spacious pool surrounded by citrus trees and terraced rows of flowers, kitchen herbs and vegetables. Despite the often unpredictable weather and high wind, the hillside blooms year round with magnolias and climbing roses, garlic, squash, peas, peaches and pomegranates. Winter brings greens such as lettuce, kale, artichokes, chard and sorrel.

Yet, long before planning her own garden, she took interest in not only growing, but studying plants. The 15-year-old turned her bedroom into a makeshift lab, spending weeks comparing normal vegetation with plants treated with radiation and chemicals. The treated vegetables' deformed shapes landed Koons first prize in botany at the Cincinnati Engineering Society Science Fair - a catalyst for questions regarding genetically modified organisms in "The Future of Food."

Her achievements don't surprise her friends, who know her as a talented, well-rounded individual. Koons Garcia "always had a great curiosity about the larger world. ... She was a natural leader and a thinker," says children's author Louise Borden of Washington, D.C., a friend since junior high. "So, her success in her recent films is not at all surprising."

Inspiring relationship

She later attended the University of North Carolina in Chapel Hill, where, after studying English for three years, she caught the film bug and continued her education by making short, fictional films before graduating in 1971.

Connected with the Earth-loving principles of the era, she became evangelical about health food and a meat-free diet. Decades later, that philosophy still thrives within the environmentalist.

"The hippies were right about an awful lot of things, but Deborah has embodied (their) finest principles and backed them up with science," says Emily MacRae, a friend of 40 years and the ex-wife of Jerry Garcia's manager, Ron Rakow.

Three years later, Koons met Garcia while on tour in New York.

"He was already in full blast. I didn't like the Grateful Dead, but I liked him," she says.

While the musician didn't exactly pick peas in his spare time, Garcia and Koons shared a passion for film. The two spent months writing letters while she briefly explored Italy's art scene.

After moving to San Francisco, Koons earned her master's in film at the San Francisco Art Institute and spent time with Garcia, exploring movies and music. Garcia knew the fine points of film and was educated in techniques, analog stock and style.

Jerry Garcia "knew so much about film on a really deep level. He was a real ally in that," she says. "We'd go to this repertory that showed old '40s, '50s films. He introduced me to Preston Sturges films and a lot of films that became my favorites."

Koons wasn't the only one inspired by the relationship.

"Deborah had an ability to make Jerry happy in a way that nobody else did. And to a degree she inspired him," MacRae says. "It wasn't long after he was with her that he decided to make a film about the Grateful Dead. There's no doubt in my mind that was to impress her." They married in 1994.

Music appreciation

Yet, even as a young filmmaker, Koons Garcia knew her work wouldn't be particularly mainstream. After making films for 30 years, including "Poco Loco" (1995), "The Future of Food" (2004), and "Symphony of the Soil" (2012), she focuses on the challenge of making moving cinematic experiences instead of making it big in the movies.

"I just like making films. I enjoy the process, but everything else connected with it is a little less interesting to me," she says.

Not surprisingly, Koons Garcia carries a deep appreciation for music - attributed to her late husband and reflected in the film. He died in 1995, and almost two decades after his death, she still draws inspiration from their relationship.

"One of the reasons I decided on the title 'Symphony of the Soil' was because music is such a wonderful thing and being around Jerry so much helped tune me to (it)."

Exploring other genres

Koons Garcia hopes her film will help people not only appreciate soil but support conservation and farming methods that are agriculturally and ecologically responsible. No matter what kind of legs the documentary will form, she plans to follow it up with "Sonatas of the Soil" - shorts on biochar, nitrogen and biosolids. Yet after 12 years of documentary work, the filmmaker hopes to cultivate her creativity for other genres.

"I feel like I've been a good member of the soil community, so I deserve a little fun. So we'll make a romantic comedy, and 25 people will see it. We'll see. ... I think it'd be fun to try."

Chronicle Garden: Three ways to show your topsoil a little love. N2

'Symphony of the Soil'

DVDs, $25, are available for presale at www.symphonyofthesoil.com and will be shipped this spring after the film's theatrical release. An educational collection of the film and "Sonatas of the Soil, Vol. 1," $20, is now available online for purchase.